Re: git: 29af6d2e2ec9 - main - msdosfs: replace '/' in direntries with '?'

Should we move this logic up into kern_getdirentries?  msdosfs is not the
only file system vulnerable to this problem.

On Thu, Jul 17, 2025 at 3:54 PM Konstantin Belousov <kib@freebsd.org> wrote:

> The branch main has been updated by kib:
>
> URL:
> https://cgit.FreeBSD.org/src/commit/?id=29af6d2e2ec9fe8df7cf1e1a0bf3597028831b18
>
> commit 29af6d2e2ec9fe8df7cf1e1a0bf3597028831b18
> Author:     Konstantin Belousov <kib@FreeBSD.org>
> AuthorDate: 2025-07-17 01:12:05 +0000
> Commit:     Konstantin Belousov <kib@FreeBSD.org>
> CommitDate: 2025-07-17 21:53:54 +0000
>
>     msdosfs: replace '/' in direntries with '?'
>
>     PR:     288266
>     Reported by:    Robert Morris <rtm@lcs.mit.edu>
>     Reviewed by:    markj
>     Sponsored by:   The FreeBSD Foundation
>     MFC after:      1 week
>     Differential revision:  https://reviews.freebsd.org/D51365
> ---
>  sys/fs/msdosfs/msdosfs_conv.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/sys/fs/msdosfs/msdosfs_conv.c b/sys/fs/msdosfs/msdosfs_conv.c
> index da4848169173..208b64930e61 100644
> --- a/sys/fs/msdosfs/msdosfs_conv.c
> +++ b/sys/fs/msdosfs/msdosfs_conv.c
> @@ -797,19 +797,24 @@ mbsadjpos(const char **instr, size_t inlen, size_t
> outlen, int weight, int flag,
>  static u_char *
>  dos2unixchr(u_char *outbuf, const u_char **instr, size_t *ilen, int
> lower, struct msdosfsmount *pmp)
>  {
> -       u_char c, *outp;
> -       size_t len, olen;
> +       u_char c, *outp, *outp1;
> +       size_t i, len, olen;
>
>         outp = outbuf;
>         if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
>                 olen = len = 4;
>
> +               outp1 = outp;
>                 if (lower & (LCASE_BASE | LCASE_EXT))
>                         msdosfs_iconv->convchr_case(pmp->pm_d2u, (const
> char **)instr,
>                                                   ilen, (char **)&outp,
> &olen, KICONV_LOWER);
>                 else
>                         msdosfs_iconv->convchr(pmp->pm_d2u, (const char
> **)instr,
>                                              ilen, (char **)&outp, &olen);
> +               for (i = 0; i < outp - outp1; i++) {
> +                       if (outp1[i] == '/')
> +                               outp1[i] = '?';
> +               }
>                 len -= olen;
>
>                 /*
> @@ -826,6 +831,8 @@ dos2unixchr(u_char *outbuf, const u_char **instr,
> size_t *ilen, int lower, struc
>                 c = dos2unix[c];
>                 if (lower & (LCASE_BASE | LCASE_EXT))
>                         c = u2l[c];
> +               if (c == '/')
> +                       c = '?';
>                 *outp++ = c;
>                 outbuf[1] = '\0';
>         }
>